Vat-dye from indirubin and process of making same.



. condensation of 1 UNITED STATES GADIENT ENGI AND JAROSLAV FROHLIOH, OF BASEL, SWITZERLAND, ASSIGNORS TO THE FIRM OF SOCIETY OF CHEMICAL INDUSTRY IN BASLE, OF

BASEL, SWITZERLAND.

VAT-DYE FROM INDIRUIBIN AND PROCESS OF MAKING SMILE- Specification of Letters Patent.

Patented Sept. 15, 1908.

Application filed April 23, 1908. Serial N 0. 428,761.

To all whom it may concern:

Be it known that we, GADIENT ENcr, doctor of philosophy and chemist, a citizen of the Swiss Republic, and resident of Basel, Switzerland, and JAROSLAV FRoHLIoH, doctor of philosophy andchemist, a subject of the Emperor of Austria-Hungary, and resident of Basel, Switzerland, have invented new and useful Vat-Dyes Derived from Indirubin and a Process of Making Same, ofwhich the following is a full, clear, and exact specification.

In the specification of the United States Letters PatentNo. 876158 dated January 7, 1908, there is described a manufacture of halogenized dyestuffs which dye in a vat, like indigo, by treating with, a halogen or with a halogenizing agent the product of isatin with indoxyl, called indirubin.

According to the present invention, valuable halogen-derivatives of indirubin may be obtained by condensing a d'ihalogen-derivative of an isatin with indoxyl or its homologues. v

A monobromo derivative of indir'ubin has already been prepared by Ad. Baeyer by condensing monobromisatin with indoxyl (See' Berliner Bem'chte, Vol, XIV page 1745), but this monobromindirubin has no practical interest, since it .has not sufficient ailinity for cotton and is not sufficient fast to washing and chlorin. On the contrary the dihalogen derivate of indirubin obtained from dihalogenisatin according to the present invention are fast to washing, light and chlorin.

The following example illustrates the invention: A solution of 31 parts of indoxyl in 4000 parts of water, or'the mass obtained by heating. an equivalent quantity of the potasviolet coloration,

by filtration, washed, to separate any unchanged dibromisatin, first with dilute soda lye and then with hot and dried.

The dried dyestuif is a brown-red powder which dissolves in concentrated sulfuric acid to a brown-violet solution from which water precipitates the dyestuif as violet flocks. It is s aringly soluble in hot benzene, more easi y in hot nitro-benzene to a red-violet solution from which it needles. Its solution in fuming sulfuric acid of 24 per cent. anhydrid is red-violet; by pouring this solution into ice-water, the dyestuff is precipitated in part without change and remains in art in solution in the form of a red-violet sul f kaline hydrosulfite vat, the dyestufl' dyes cotton red-violet tints fast to washing, light and chlorin, which are much more reddish than Water, and is pressed.

crystallizes as brown-red the dyeings obtained with the dibromo-indirubin prepared by bromination of indirubin as prescribed in specification of United States Letters Patent No. 876,158.

In like manner dyestuffs are made bycondensing dibromisatin with homologues of indoXyl, as for instance methylindox l. The dibromisatin can also be replaced y other dihalogenated isatin-derivati'ves, as for instance dibromo-alphanaphtisatin, dibromobetanaphtisatin, dichlorisatin melting at 205208 O., chlorobromisatin melting at 233 to 234 (3., (obtained by chlorinating bromisatin in glacial acetic acid), bromochlorisatin melting at 243 to 246 C. (obtained bybrominating chlorisatin in glacial acetic acid), whereby dyestuffs of analogous properties are obtained.

What we claim is:

1. The herein described process for the manufacture of dihalogen derivatives of indirubin, which consists 1n condensing a dihalogen-derivative of an isatin with an indoxyl compound. I

2; As new products, dihalogen derivatives of indirubin, obtainable by the condensation of one molecule of a dihalogenated isatinderivative with one molecule of an indoxylcompound, constituting in dry state brownish red ppwders, dissolvingin concentrated sulfuric acid with a dirtybrown-violetto dissolving in fuming sulfuric acid of 24 per cent. S0 with a, violet signed our names this 14th day of April 1908, color, being spsringl soluble in hot benzene, in the presence of two subscribing witnesses. 10 more easily in hot mtrobenzene with a violet 1 ADIENT ENGI coloration and yielding, when treated with E AV FROHLIGH alkaline reducing agents yellowish vets, dy'e- J in cotton violet tints fast to Washing and Witnesses: ebiorin. Gino. GIFFORD,

In witness whei 'eof We have hereunto AMAND BITTER. 

